Showing papers by "Mashrur Chowdhury published in 2011"

University traveler value of potential real-time transit information

Abstract: Intelligent transportation systems (ITS) have become common in public transit systems, particularly providing real-time transit information. For new implementations, it remains difficult to predict and quantify system and user benefits of technology implementation. Although previous studies have quantified the operational benefits of real-time transit traveler information systems, a gap in knowledge exists around passenger benefits of such systems. The objective of this research was to create a refined method for evaluating transit rider benefits from real-time traveler information and predict changes in traveler behavior. The study was conducted on a rural university campus, isolating the impacts of the system from the multiple influences that often affect transportation in larger metropolitan areas. This study uniquely integrated transit system performance, pedestrian travel times, and traffic simulation to determine travel times and predict mode split. Findings indicated that reducing passenger waiting anxiety was the most significant measure of traveler benefit from such a system. While the benefits found were specific to the study site, the methodology can be used for other transit systems evaluating real-time transit technology investments in rural or urban environments.

An Integrated Tool for Modeling the Impact of Alternative Fueled Vehicles on Traffic Emissions: A Case Study of Greenville, South Carolina

Abstract: The United States recently has been investing heavily in renewable energy technologies to reduce dependence on foreign oil and cut greenhouse gas emissions. The impacts of using alternative transportation fuels have also attracted significant attention. This research focuses on evaluating the environmental impacts of three alternative transportation fuels: electricity, ethanol and compressed natural gas. The goal is to estimate the impacts of alternative fueled vehicles at a project level in terms of daily fuel savings and emission reduction. In this research, a review of the environmental impacts of alternative transportation fuels is performed. In addition, a case study is conducted using the Environmental Protection Agency’s (EPA) latest vehicle emission model, MOVES, and the PARAMICS microscopic traffic simulation tool to analyze the emission impacts of alternative transportation fuels for a road network in Greenville, South Carolina. For each alternative transportation fuel considered in this study, its emission and fuel consumption impacts are evaluated based on different market shares. The results show significant positive environmental impacts from using the three alternative transportation fuels. The findings of this paper can be useful to other transportation researchers and practitioners in conducting environmental impacts studies using MOVES.

Evaluation of different contraflow strategies for hurricane evacuation in Charleston, South Carolina

Abstract: Limited specific evidence is available on the effectiveness of using contraflow as an evacuation traffic management tool. This study was conducted to determine the best combination of strategy options for evacuating Charleston, SC, along route I-26 during the event of a hurricane or other events. PARAMICS microscopic traffic simulator was used to evaluate the impact of each combination of evacuee response timing and traffic control strategy, such as contraflow, with respect to average vehicular travel time and evacuation duration. Analysis revealed the combination of management strategies that created the lowest evacuation durations and travel times for several types of anticipated evacuee responses. Furthermore, a proposed reconfiguration of the I-526/I-26 interchange for contraflow operations produced additional savings in travel times and evacuation durations. These findings support the use of all lanes for contraflow during all evacuations and provide justification to examine a possible reconfiguration of the I-526/I-26 interchange for use during evacuations.

A simulation modeling framework for community-wide evacuation planning

Abstract: Simulation is a useful and cost effective tool for evacuation planning. However, extensive data collection and preparation is necessary to build a traffic evacuation simulation model that can closely replicate real life conditions. In a community-wide evacuation process during an emergency, which covers hundreds of miles, input data related to simulation of traffic evacuations include (1) Traffic and roadway geometry, (2) Geographic distribution of the affected area, (3) Travel demand modeling, and (4) Behavioral analysis of potential evacuees. This paper presents a framework for preparing simulation inputs and ultimately developing a simulation model. Brief excerpts from a case study on the evacuation of Charleston, South Carolina are also included. An accurate input analysis is very important to the success of a simulation project since without correct input data, the output of a simulation cannot contribute to more effective decision making. This paper presents a simple and efficient methodology for data preparation regarding a large scale city evacuation simulation involving long distance trips.

Vehicle-Infrastructure Integration-Enabled Plug-in Hybrid Electric Vehicles for Optimizing Energy Consumption

Abstract: As the market share of hybrid electric vehicles (HEVs) increases to reduce the dependency on fossil fuels and there is an increased interest in real-time communication between vehicles and infrastructure, the integration of these two technologies has become an important research topic. Such an integrative paradigm, envisioned in the Vehicle-Infrastructure Integration (VII) or IntelliDrive systems, can improve mobility and increase safety. In this paper, a VII-HEV framework is proposed for utilization for both conventional HEVs and Plug-in Hybrid Electric Vehicles (PHEV). The data collection and communication capability of these VII’s permits the prediction of speed profiles at the vehicle level within a reasonable error rate. Once predicted, the speed profile is sent from roadside units (RSUs) to VII-HEV/PHEVs for optimization. The authors describe the use of the Equivalent Consumption Minimization Strategy (ECMS), which optimizes energy usage of PHEVs and HEVs with the predicted speed profile obtained through the VII system. A simulation analysis of the framework with 65 driving cycles shows improvement of energy consumption of 2% to 12% with an average of 6% for PHEVs and 1% to 3.5% with an average of 2.2% for HEVs.

Using a GIS-based, Hitchcock algorithm to optimize parking allocations for special events

Abstract: Clemson, a small college town in South Carolina, deals with a massive over-saturation of its transportation system during special events, especially during home football games, resulting in total system failure. This research has developed a methodology to optimize parking, using a Geographic Information System (GIS)-based transshipment algorithm, and it has produced great time savings compared with the individual, “manual” efforts of thousands of drivers attempting to find spaces where available. As such, this research constitutes an effective implementation of the Hitchcock Transportation Algorithm for solving a transshipment problem applied to parking lot distribution. Because the Hitchcock Algorithm considers the network cost for distributions, it gives very realistic solutions, and so a system equilibrium that minimizes overall system delay has been achieved through optimal parking assignment combined with pre- and post-game traffic control strategies. This has been validated using a simulation model that was developed for evaluating the strategies.

Analysis of Cost Estimation Disclosure in Environmental Impact Statements for Surface Transportation Projects

Abstract: Reliability in cost estimates in publicly funded projects is more important today than ever with increased governmental funding to infrastructure projects and associated accountability requirements, but surface transportation projects, large and small, in the United States have a legacy of cost overruns. The problems with these overruns start with the cost estimation process before projects begin. Studies have shown that early cost estimations reflect best-case scenarios rather than realistic expectations, and have attributed technical, economic, psychological, and political reasons for underestimation. The primary objectives of this research were to determine how costs have been presented and updated in environmental impact statements, to identify endemic technical problems with cost estimation during the environmental review of surface transportation projects, and to develop recommendations for improving cost estimation and disclosure. Cost estimation methods were analyzed from the documents of 100 projects, including draft environmental impact statements, final environmental impact statements, and records of decision. The study concluded that the lack of guidance on how to include cost estimation in environmental review revealed itself in the level of detail and attention given to estimating costs. Agencies omitted or included various aspects of cost estimation randomly. Professional organizations should fill the gap of the need for specific guidance to cost estimation for environmental review so it can evolve as a state of the practice.

Subaqueous Cohesive Sediment Gravity Flows from Open Water Pipeline Dredge Disposal: Laboratory Experiments and Mathematical Modeling

Abstract: Subaqueous sediment gravity flows generated in open water pipeline dredge disposal operations were investigated through laboratory experiments and mathematical modeling. Three laboratory experiments that simulate typical open water pipeline dredge disposal operations in the coastal environment were conducted by discharging mud slurries with three different initial concentrations in a large pool. The discharged mud slurries descended as vertical buoyant jets through the water column. After impinging the bottom, they formed a short-lived momentum-driven axisymmetric horizontal flow that transformed into an axisymmetric gravity flow soon after. The analysis of the radial spreading of those fluid mud gravity flows showed that their flow dynamics were governed by a balance between the driving buoyancy force and the resisting inertia force. A simple mathematical model (compositional box model) that does not consider the presence of suspended sediment was used to predict the experimental observations. The predictions of the box model solution were observed to be notably in good agreement with experimental observations, despite the box model exhibiting several simplifying assumptions. It is concluded that the radial propagation of fluid mud gravity flows in the inertia-buoyancy propagation phase can be modeled by a compositional box model solution. This study is motivated by the need for deterministic predictive modeling capabilities for coastal dredging operations.

Transit System Evaluation Process: From Planning to Realization

Abstract: This article presents a methodology for evaluating transit in the context of overall mobility. Planning, operations and performance measurement activities were integrated into a comprehensive framework designed to evaluate a fixed-route transit system for a university or a city with a predominant academic institution. The evaluation process involved: identifying users and stakeholders; reviewing planned expansion and renovations; reviewing transit agency’s goals and objectives; defining and refining transportation goals and objectives; evaluating existing economic and transportation conditions; benchmarking against peer cities or universities; developing and evaluating alternatives; developing and enhancing the plan; guiding stakeholder consensus; developing an performance-management strategy; establishing baseline and implementing strategies; and monitoring and reporting performance. This framework allows for continual feedback to achieve optimal performance of the transit system. The proposed process was applied to the on-campus transit route at Clemson University in South Carolina to demonstrate the framework’s effectiveness.

Identification of Causal Factors of Bridge Failure through Fault-Tree Analysis and Intelligent Sensor Solutions

Abstract: Bridges are the lifelines of the United States surface transportation network and support the growth of our nation’s economy; however, rapid economic growth over that past few decades has stretched the design capacity of many bridges in the United States In recent years, there have been several incidents of bridge collapse, which calls for an urgent need to develop a systematic method of assessing the failure risks and identifying the initiating events that can lead to a bridge collapse This paper presents a process of bridge failure risk analysis through fault-tree modeling and identifies potential structural health monitoring(SHM)-based intelligent sensors as countermeasures This research concluded that integrating SHM sensors with Intelligent Transportation Systems (ITS) is a cost-effective way to monitor nation’s transportation infrastructure for both structural and operational problems

The Relationship of SCDOT Damage Claims and Lawsuits to Roadway Engineering Safety Issues

Abstract: South Carolina Department of Transportation (SCDOT) processes approximately 1000 claims per year and is engaged in 100 lawsuits per year. These claims and lawsuits most often are filed as a result of the claimant believing something about our highway system is flawed and this caused them harm for which they are seeking damages. Through an analysis of SCDOT's claims and lawsuits, it is possible to discern a pattern or gain information about the frequency and types of claims and lawsuits, and the corresponding crash or incident that gave rise to them. The desired result is to provide SCDOT with a proactive approach for eliminating or ameliorating the types of highway conditions that are alleged by plaintiffs to contribute to causes of crashes or incidents. Through such an approach, future lawsuits and claims can be reduced. Studying patterns of previous cases found in favor of the plaintiff may also help to build stronger defense cases for the SCDOT or provide direction for changes in legislation to stop potentially frivolous cases.